Surgical instrument with magnetic clamping force

Abstract

A surgical instrument comprising an end effector, the end effector comprising first and second opposing jaw members, wherein at least one of the first and second jaw members are moveable such that the first and second jaw members are transitionable between open and closed positions. The first jaw member may comprise a permanent magnet. The second jaw member may also comprise a magnet (e.g., permanent or soft). The magnetic motive force between the magnets of the first and second jaw members may attract each other to thereby reduce the external force required to transition the first and second jaw members to the closed position. In addition, the magnets may be configured to repeal each other to thereby aid in opening the jaw members.

What is claimed is: 
     
       1. A surgical instrument comprising:
 an end effector comprising:
 a first jaw member comprising a first magnet, wherein the first magnet comprises a first electromagnet; and 
 a second jaw member opposing the first jaw member, wherein the second jaw member comprises a second magnet, and wherein at least one of the first and second jaw members are moveable such that the first and second jaw members are transitionable between open and closed positions, and wherein a magnetic motive force between the first and second magnets reduces an external force required to transition the first and second jaw members to the closed position 
 
 a control circuit for controlling the first electromagnet; and 
 a position sensor for sensing a distance between the first and second jaw members, wherein the position sensor is in communication with the control circuit, and wherein the control circuit is responsive to the position sensor in controlling the first electromagnet. 
 
     
     
       2. The surgical instrument of  claim 1 , wherein the second magnet comprises a soft magnet. 
     
     
       3. The surgical instrument of  claim 2 , wherein the soft magnet comprises a soft magnetic material selected from a group consisting of steel, nickel-iron alloy, and nickel-cobalt alloy. 
     
     
       4. The surgical instrument of  claim 1 , wherein the second magnet comprises a second permanent magnet. 
     
     
       5. The surgical instrument of  claim 4 , wherein the second permanent magnet comprises a permanent magnetic material. 
     
     
       6. The surgical instrument of  claim 5 , wherein the permanent magnetic material is selected from a group consisting of iron, nickel, cobalt, neodymium, and samarium. 
     
     
       7. The surgical instrument of  claim 4 , wherein the second permanent magnet comprises a second electromagnet. 
     
     
       8. The surgical instrument of  claim 1 , wherein the surgical instrument is selected from a group consisting of a RF surgical instrument, a harmonic surgical instrument, an endo-cutter, and a grasper. 
     
     
       9. The surgical instrument of  claim 1 , further comprising a pressure sensor for sensing a force being applied to tissue positioned between the first and second jaw members, and wherein:
 the pressure sensor is in communication with the control circuit; and 
 the control circuit is additionally responsive to the pressure sensor in controlling the first electromagnet. 
 
     
     
       10. The surgical instrument of  claim 9 , further comprising:
 a trigger arm; and 
 a trigger sensor for sensing retraction of the trigger arm by a user of the surgical instrument, wherein:
 the trigger sensor is in communication with the control circuit; and 
 the control circuit is additionally responsive to the trigger sensor in controlling the first electromagnet. 
 
 
     
     
       11. A surgical instrument comprising:
 an end effector comprising:
 a first jaw member comprising:
 a magnetic side portion; and 
 a magnetic middle portion that is a switchable permanent magnet having a longitudinal axis, wherein the magnetic middle portion is rotatable about the longitudinal axis independent of rotation by the magnetic side portion; and 
 
 a second jaw member opposing the first jaw member, wherein the second jaw member comprises a second magnet that is a permanent magnet, and wherein at least one of the first and second jaw members are moveable relative to each other such that the first and second jaw members are transitionable between open and closed positions, and wherein, attraction and repellent magnetic motive force between the first and second magnets may be adjustable upon rotation of the magnetic middle portion about the longitudinal axis, wherein, upon rotation to a first position independent of rotation by the magnetic side portion of the first magnet, the magnetic motive force between the first and second magnets reduces an external force required to transition the first and second jaw members to the closed position. 
 
 
     
     
       12. The surgical instrument of  claim 11 , wherein:
 the magnetic side portion comprises first and second ferromagnetic sidepieces separated by a non-ferrous middle portion; 
 the magnetic middle portion is rotatable within a bore defined in the first jaw member; and 
 the magnetic middle portion comprises opposing magnetic poles.